LOS ANGELES — This wasn’t the first time Shay Rose went viral.

But it was the biggest.

In her 21 years, the social media star — Shay Rose is a pseudonym — has built a mammoth following on TikTok and Instagram with handmade whimsical costumes that re-create looks from Disney princesses to Lady Gaga.

When the pandemic began, Rose moved from the UCLA dorms back in with her family in Orange County. As cases climbed in September, she wondered: “Wouldn’t it be nice to have your own social distancing bubble?”

She had plenty of pink tulle on hand, and besides, wouldn’t it be fun to make a dress with a 6-foot radius?

By the end of November, the finished project had racked up 3.9 million likes and 16.8 million views on the social media platform TikTok. It took two months and more than 350 feet of tulle but, as Rose speculated on Instagram, sometimes creating is rewarding. Other times, it can be exhausting. And sometimes it’s both.

“Virality is really just what people want to see,” Rose told The Times. “For me, it’s making the stuff that I’m curious about and the stuff that I want to make. Usually people want to see it, too.”

Of course, she qualified, there’s a lot more to a viral secret sauce than that, including the behind-the-scenes technicalities, formatting and editing of content. Rose joins a wave of teens and 20-somethings who dedicate themselves to creating — content, clothes or both.

“But in the end, it’s just like: If you make stuff that you’re curious about, there’s usually a niche for it,” Rose said. “Other people are curious about it, too.”

Luckily, she lives in sunny Orange County, because the dress was so enormous (12 feet in diameter with a 113-foot surface area) that she had to work on it outside. The design breaks down into two pieces, the bodice and the base; the latter includes a PVC grid for the dress to sit on, complete with wheels.

“There’s no way it can fit through a door, so it’s in no way ever going to be practical,” Rose said. “But my idea behind it was just that question of, ‘Oh, what if? Would this even work? What would it look like?’”

The short answer: Yes. It would work, after countless attempts at making the base stable enough to stop caving in. And it would look like something out of a 2020 fairy tale, a billowing, bubble-gum-pink gown with a mask to match.

Rose documented the process from start to finish on her social media accounts. That translates to two TikToks, three Instagram Reels, seven Instagram posts and no fewer than 72 Instagram Stories, carefully curated in a Highlight.

The communication studies major is a digital native. While the debate over the Gen Z/millennial cusp rages on TikTok, Rose falls solidly into the first camp. She’s spending quarantine at home, where she balanced part of her last year of school with a six-month internship at TikTok, which she recently finished during finals week. In other words, she understands the ins and outs of the internet. “Whenever you know a platform and you love a platform,” she said, “it’s so easy to be passionate and love to go to work every day.”

Her first cosplay was a happy accident: In eighth grade, she dressed as a character from the novel series “The Lunar Chronicles” to attend a book signing — without realizing that it was “cosplay,” or performance art through dressing as a character. In 2015, she re-created Anna’s coronation dress from “Frozen” using what she had around the house: Her brother’s old curtains and gold Christmas ribbon.

“It was basically like a puzzle … to figure out: ‘How do I make this thing work?’” her mom told The Times. (The mother did not want to be identified, an effort to help her daughter maintain a bit more anonymity on the internet.) “I kept telling her, ‘They have patterns. You could just buy a pattern; it’d be so easy.’ ‘No, Mom. No, Mom. This is not how I do it. I’m gonna figure it out myself.’ And she taught herself how to sew.”

From there, Rose grew a following first on cosplay forums, then on Instagram dressing as everyone from Deku (“My Hero Academia”) and White Diamond (“Steven Universe”) to Disney princess Belle and 20th Century Fox’s Anastasia.

“But I don’t consider my main account,

@crescentshay, to be a cosplay account because there’s so much more to cosplay than just making a costume and putting it on,” Rose said. “It’s a really, really tight-knit community.”

She amassed a sizable following, mostly among the cosplay community she came up through. In August of last year, her main @crescentshay Instagram account had 41,500 followers.

Then she joined TikTok last summer, and her first viral project — “Beauty and the Beast”-inspired shoes — took off “when TikTok was a baby,” Rose said. “It was before TikTok was cool.”

Those “Disney shoes” feature tiny clay roses encased in clear heels. Inspired by the brand Irregular Choice, known for its ornate embellished heels, the project blew up in September 2019, reaching 1.5 million likes and 8.9 million views on TikTok.

“I had been doing this whole crafting thing online for a while, but it had never really taken off in the mainstream,” Rose said. “And then all of a sudden, it wasn’t just me and my cosplay friends watching my stuff; it was everyone.”

After the Disney shoes, her following more than doubled in a month.

When she went viral on TikTok, she became the only cosplayer some users followed. They followed her expecting more mainstream design or crafting and were bewildered by her cosplay content. This sparked a “bit of a life crisis.” Between October 2019 and January 2020, she lost almost 10,000 followers.

“There came this point where I was like, ‘OK, do I want to be a cosplayer? Or do I want to be more mainstream?’” Rose said. “Because I feel like with cosplay there’s a limit to how much you can show your art to people, because it is kind of a niche.”

After reaching more than half a million followers on Instagram and 2.7 million on TikTok, Rose has separated her main from her “side” account (which boasts 11,800 followers). There, she posts more personal updates: Herself, her friends, her aerial acrobatics hobby and her cosplay looks.

“That divide really helped me, because it’s hard to put yourself online,” Rose said. “And in this way, I have created a little bit of a separation between my art and myself.

“You try your best not to care. But numbers hurt. And it’s weird when it doesn’t just feel like people don’t like your work but they don’t like you.”

Rose leans perhaps the most heavily on the shoulder of her therapist. She “lucked out,” she said, by starting therapy about half a year before her first viral moment. In fact, she ducked out of this interview for a moment to reschedule an appointment.

“Every week, I would talk to my therapist and be like, ‘This is going viral. And I feel really terrible,’” Rose said. “It’s cool to have someone that you trust, that’s

level-headed, to be like, ‘Why does this matter?’ And to ground you again.”

Now, with a handful of viral creations under her belt, Rose has built up a support system: Friends, family, co-workers and connections in the digital media industry. Her No.1 supporter? Her mom, who also photographs most of Rose’s projects.

“I feel so much more comfortable doing the shoot with her, because behind the camera, she’s always like, ‘Go! You look beautiful!’” Rose said. “Like, ‘Oh, my gosh, stunning! Do a twirl!’ It’s so funny because I edit through all the audio of the video she takes, and it’s all her just shouting encouragement.”

Rose’s mother and father, who sometimes plays a supporting role in her work, approve of her side hustle. As a college senior, Rose’s last six months of classes have gone virtual, so — like many others in her situation — she has moved back in with her family, which is part Iranian, part Chinese and part Lithuanian.

Her parents also support her postgrad plan: To try out being a full-time content creator and artist, at least for a year. Rose knows herself, she said, and knows she can hustle her way back into the corporate world if need be.

“I’m a realist enough to the point where I don’t know if this is going to be a forever thing,” she said. “And I’m always keeping my options open to come back to a more stable job. But I know I’d regret it if I didn’t try it.”